Bladder Cancer: Root of 'Untreatable' Disease Identified

A single type of cancer stem cell has been identified as the source of the most aggressive and invasive bladder cancers, according to a new study.

The study, published in the peer-reviewed scientific journal Nature Cell Biology, details how researchers associated with the Stanford University School of Medicine identified a single type of cell in the lining of the bladder that causes invasive bladder cancer.

According to the researchers, invasive bladder cancer affects more than 375,000 people across the world each year. The cancer, which spreads to replace the entire lining of the bladder, is largely untreatable.

Philip Beach, a co-author of the study, said in a press release that the cancer is so difficult to treat because cancer cells practically root themselves in the bladder lining, even before actually causing harm to a patient.

"All of these cells have already taken several steps along the path to becoming an aggressive tumor," the researcher explained. "Thus, even when invasive carcinomas are successfully removed through surgery, this corrupted lining remains in place and has a high probability of progression."

So how does one treat it? Like with any invasive infection, physicians have to essentially kill it at the source. In this case, researchers looked for the source by exposing lab mice to a known carcinogen called N-butyl-N-4-hydroxybutyl nitrosamine (BBN). The BBN was regularly placed in the mice's drinking water and the animals were then observed over a period of several months. After six months, all mice had developed invasive bladder cancer.

The researchers then repeated this experiment using a fluorescent marking agent to help identify the spread of cancer from suspected sources. In the most successful experiments, adult stem cells in the bladder lining that expressed a signaling protein strangely known as "sonic hedgehog" (SHH - commonly associated with limb and even shark penis development) were identified with the marking agent, highlighting cells that arose from these stem cells. Researchers found that after exposing the mice to BBN, the resulting cancer cells in the bladder all appeared to be highlighted with the marking agent, indicating that they originated from the SHH-expressing cells.

This is exciting news for researchers because knowing the cancer's source can help scientists develop new ways to try and fight what was once thought to be a largely untreatable form of cancer.

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